Gathmann & Tscharntke (1997) monitored solitary bees and wasps nesting in reed stem nest boxes placed on three set-aside fields sown with a clover grass mix in Germany over three years. Relative to nest boxes placed in semi-natural grasslands, few species occupied these nest boxes (quantitative details are lacking from the report of this trial).

A replicated trial from 1994 to 1996 in central Germany (Gathmann & Tscharntke 1997) found that reed Phragmites australis stem nest boxes were occupied by 13 species of bee (Apidae), 19 species of wasp and 17 species of parasite and parasitoid (Hymenoptera). In total, 8,303 nests were made. The number of occupied stems almost doubled over three years from 1,761 in 1994 to 3,326 in 1996. One-hundred-and-fifty reed stem nest boxes (plastic tubes filled with 150 lengths of 20 cm reed stem) were placed at 15 different sites. Three replicates in each of five habitat types were studied: sown field margin strips, set aside fields (sown with clover Trifolium spp.-grass mixture), extensively used grassland, chalk grassland, orchard meadows. Ten reed stem nest boxes were placed in each site. In autumn, nests were dissected and occupants identified. This study is also referred to by (Tscharntke et al. 1998)).

In a replicated trial in central Germany from 1994-1996, 150 reed stem nest boxes (plastic tubes filled with 150 ´ 20 cm lengths of reed stem) placed at 15 different sites were occupied by 13 species of bee, 19 species of wasp and 17 species of parasite and parasitoid (Gathmann & Tscharntke 1997, also referred to by Tscharntke et al. 1998). In total, 8,303 nests were made.

A replicated trial from 1994 to 1996 in central Germany (Gathmann & Tscharntke 1997) found that few solitary bee and wasp (Hymenoptera: Aculeata) species occupied reed Phragmites australis stem nest boxes in set-aside fields sown with a clover-grass mix relative to nest boxes placed in semi-natural grasslands (quantitative details are lacking from the report of this trial). Three replicates in each of five habitat types were studied: set-aside fields (sown with clover-grass mixture), sown field margin strips, extensively-managed grassland, chalk grassland, orchard meadows. Ten reed stem nest boxes were placed in each site. In autumn, nests were dissected and occupants identified. This study is part of the same study set-up as Gathmann & Tscharntke 2000.

In a replicated trial on field margins, set aside fields and extensively managed meadows in central Germany from 1994-1996, 150 reed stem nest boxes (plastic tubes filled with 150 ´ 20 cm lengths of reed stem) were placed at 15 sites (Gathmann & Tscharntke 1997). The number of occupied stems almost doubled over three years from 1,761 in 1994 to 3,326 in 1996.